The present invention relates to textiles and, more particularly, to a method for binding a full or partial metal plating to the fibers of a textile, and the metallized textile thereby produced.
There are a variety of applications for which a textile with a full or partial metal or metal oxide plating bonded to the fibers thereof would be useful. These include:
1. Acaricide
Beds commonly are infested by tiny mites. These mites eat bacteria and fungi that grow on epidermal scales shed by people who sleep in the beds. Fragments of dead mites, and mite excreta, are allergens, to which asthmatics and people with dust allergens are sensitive. It has been found that some metals and metal oxides, notably Cu, CuO, Ag and Ag.sub.2 O, repel mites.
The conventional method for making textiles inhospitable to mites is to treat the textiles with an organic acaricide such as benzyl benzoate. For example, Bischoff et al., in U.S. Pat. No. 4,666,940, teach an acaricide that includes benzyl benzoate and a solid powder carrier whose particles are of a size suitable for ingestion by the mites. These acaricides must be replaced every time the textile is laundered. Thus, Bischoff et al. recommend using their acaricide on textiles, such as carpets and upholstery, that are not laundered frequently. An inherently acaricidal bedsheet would keep a bed free of mites, even after multiple launderings, without the need to reapply acaricide to the bedsheet.
2. Bactericide and Fungicide
Some metal oxides, notably ZnO, are well known as fungicides. Before the introduction of antibiotics to medicine, silver metal sometimes was used as a bactericide and bacteriostat. Textiles with inherent bactericidal and fungicidal properties have obvious applications in settings, such as hospitals and similar institutions, where it is important to maintain aseptic conditions.
Bactericidal agents used heretofore in textiles include complexes of zirconyl acetate with inorganic peroxides (Welch et al., U.S. Pat. No. 4,115,422), metal cations contained in zeolite particles (Hagiwara et al., U.S. Pat. No. 4,525,410), and quaternary ammonium salts (White et al., U.S. Pat. No. 4,835,019; Hill et al., U.S. Pat. No. 5,024,875; Zhao et al., U.S. Pat. No. 5,254,134). These are not totally satisfactory, being specific to a particular textile (such as the polyamide yarn of White et al.), or being subject to eventual loss of activity by chemical decomposition, a process often hastened by laundering.
The methods known in the prior art for bonding a metal or a metal oxide to a textile generally require that the metal or its oxide be bonded indirectly to the textile. For example, the metal may be reduced to a powder and suspended in a binder. The binder metal mixture then is applied to the textile, with the binder, and not the metal, bonding to the textile. Alternatively, the metal is reduced to a powder, an adhesive is applied to the textile, and the metal powder is spread on the adhesive. Examples of both such methods may be found in U.S. Pat. No. 1,210,375, assigned to Decker. These methods are less than satisfactory for the above applications, for at least two reasons. First, the carrier or adhesive may entirely encapsulate the metal or metal oxide powder particles, inhibiting their contact with mites, fungi, and bacteria, and making the textile useless as an acaricide, fungicide, or bactericide. Second, multiple launderings tends to weaken the binder or adhesive and loosen or remove the particles.
Two notable exceptions to the general rule that metals and metal oxides have not heretofore been bonded directly to textiles are nylon textiles and polyester textiles, which may be plated with metals using standard electroless plating processes for plating plastics. The specific electroless plating methods known to the art are restricted in their applicability to only certain plastics, however. In particular, they are not suited to natural fibers, nor to most synthetic fibers.
There is thus a widely recognized need for, and it would be highly advantageous to have, a textile with a full or partial metal or metal oxide plating directly and securely bonded to the fibers thereof, for use in the applications listed above.